1. Field of the Invention
The present invention relates to a light source system and a projector.
2. Description of the Related Art
In these days, data projectors are used on many occasions as image projection apparatuses which project images including images on screens of personal computers and video images, as well as images based on image data which is stored in memory cards on to a screen.
These projectors are such that light emitted from a light source is collected on to a micromirror device called a DMD (Digital Micromirror Device) or a liquid crystal plate for display of color images onto the screen.
In association with the propagation of video equipment such as personal computers and DVD players, the application of such data projectors is widened from use for presentations on business occasions to home use.
In these projectors, conventionally, the mainstream has been projectors using a high-intensity discharge lamp as alight source. However, in recent years, there have been made many developments on projectors which use, as a light source, a semiconductor light emitting element such as a laser diode.
For example, there have been proposed light source systems which include an excitation light source which emits light of blue wavelength band by a laser diode and a luminescent wheel (a rotary plate) which has a luminescent layer which absorbs light emitted from the excitation light source to convert it into visible light and which is driven to rotate by a motor, and projectors including such light source systems.
However, in the event that the luminescent wheel is used for a long period of time, there may occur a case where unevenness is caused in an area of the luminescent wheel on to which excitation light is shone due to large optical energy of excitation light. Then, in the event that unevenness is so caused, the deterioration speed of the luminescent material is increased at the portion where such unevenness is caused, resulting in a risk that color spots are generated in the luminescent material.
To cope with a problem like this, Japanese Unexamined Patent Application No. 2006-98979 discloses a projector in which the illuminating operation of a lamp is controlled in accordance with the rotational state of a luminescent wheel.
However, the projector disclosed is such that the lamp is not illuminated when the luminescent wheel is not rotated and does not take into consideration the suppression of deterioration of a luminescent material on the luminescent wheel due to a change with time based on unevenness generated in a working area of the luminescent wheel and generation of color spots in the luminescent material.